K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2020-08-16T20:57:02.755026Z
K 7
svn:log
V 661
vm_object: allow paging_in_progress to be acquired after object termination.

The vm objects are type-stable, and can be accessed even after the
last reference is dropped, or in case of vnode objects, after vgone()
destroyed it as well.

Stop asserting that pip == 0 after vm_object_terminate() waited for
existing owners to drop it, we only want to drain them before setting
OBJ_DEAD flag.  Also stop asserting pip == 0 in object destructor.

Update comments explaining the interaction between paging_in_progress
and termination.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D25968

END